On Fri, Jun 18, 2021 at 10:06 PM Alexey Kondratov <kondratov.alek...@gmail.com> wrote: > On Fri, Jun 18, 2021 at 5:42 PM Andrey Borodin <x4...@yandex-team.ru> wrote: > > > > If we run 'pg_rewind --restore-target-wal' there must be restore_command in > > config of target installation. But if the config is not within > > $PGDATA\postgresql.conf pg_rewind cannot use it. > > If we run postmaster with `-c > > config_file=/etc/postgresql/10/data/postgresql.conf`, we simply cannot use > > the feature. We solved the problem by putting config into PGDATA only > > during pg_rewind, but this does not seem like a very robust solution. > > > > Yeah, Michael was against it, while we had no good arguments, so > Alexander removed it, IIRC. This example sounds reasonable to me. I > also recall some complaints from PostgresPro support folks, that it is > sad to not have a cli option to pass restore_command. However, I just > thought about another recent feature --- ensure clean shutdown, which > is turned on by default. So you usually run Postgres with one config, > but pg_rewind may start it with another, although in single-user mode. > Is it fine for you? > > > > > Maybe we could add "-C, --target-restore-command=COMMAND target WAL > > restore_command\n" as was proposed within earlier versions of the patch[0]? > > Or instruct pg_rewind to pass config to 'postgres -C restore_command' run? > > Hm, adding --target-restore-command is the simplest way, sure, but > forwarding something like '-c config_file=...' to postgres sounds > interesting too. Could it have any use case beside providing a > restore_command? I cannot imagine anything right now, but if any > exist, then it could be a more universal approach. > > > > > From my POV adding --target-restore-command is simplest way, I can extract > > corresponding portions from original patch. > > > > I will have a look, maybe I even already have this patch separately. I > remember that we were considering adding this option to PostgresPro, > when we did a backport of this feature. >
Here it is. I have slightly adapted the previous patch to the recent pg_rewind changes. In this version -C does not conflict with -c, it just overrides it. -- Alexey Kondratov
v1-0001-Allow-providing-restore_command-as-a-command-line.patch
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